1. Field of the Invention
The present invention relates to a coreless rubber crawler having a peripheral main cord and a reinforcing cord disposed on an outer periphery thereof embedded in a main body.
2. Description of the Related Art
As a crawler belt that enables a vehicle to run on a muddy road without slipping by decreasing a grounding pressure (pressure from ground) on the road where the vehicle runs, rubber crawlers that do not damage the road have been frequently employed in recent years.
Such rubber crawlers are roughly classified into a rubber crawler having cores that are widthwise disposed in an endless rubber crawler at some intervals along its longitudinal direction to be embedded in the endless rubber crawler, and a coreless rubber crawler having only reinforcing cords embedded in an endless rubber crawler. A snowmobile, agricultural vehicle (machine) or relatively small vehicle (machine) for construction adopts mainly the latter coreless rubber crawler. FIG. 5 shows an example of the structures of the coreless rubber crawler.
In the coreless rubber crawler, a peripheral main cord 22 has been embedded in a main body 21 excluding grounding lugs 25 and guide projections for wheel rotation (or driving projections) 24 at the shallow location (about 10 mm or less) with respect to the inner peripheral surface.
Bias cords 23 are disposed in the inner or outer side of the main cord 22 (outer side in case of the figure) to enhance the transverse rigidity of the rubber crawler 21, and further a cord (layer) crossing at right angle (cord layer having a cord angle crossing with the peripheral direction at right angle) is provided.
In the coreless rubber crawler, there has been no example of studying deeply the depths of theses cords embedded in the main body.
Generally, the main cord embedded in the main body of the rubber crawler scarcely extends in the peripheral direction, and therefore the main cord constitutes a neutral line of the main body of the rubber crawler.
In case the main cord (i.e., neutral line) is embedded at a shallow location with respect to the inner periphery, a grounding portion corresponding to the outer periphery is remote from the neutral line. Therefore when the crawler is rounded (entrained) about driving wheels and idlers to conduct a rotation driving, an amount of deformation strain of the main cord is apt to increase to promote deterioration of the rubber by its use for a long period.
The object of the present invention is to provide a rubber crawler which solves the above-mentioned problems relating to the conventional coreless rubber crawler and which is capable of enhancing the durability by canceling the difference between amounts of deformation strains in the rubber main body and capable of controlling separation from the crawler of the wheels by maintaining the transverse rigidity.
The present invention is provided by a coreless rubber crawler having a peripheral main cord and a reinforcing cord disposed on an outer periphery thereof embedded in a main body having a thickness T, wherein an embedded depth H of the cord embedded in an outermost peripheral layer of the main body satisfies Hxe2x89xa7xc2xdxc3x97T, the depth being measured from an inner peripheral surface of the main body.
Further, the invention is provided by the coreless rubber crawler wherein the main cord is embedded in the main body such that the embedded depth H of the main cord, which is measured from an inner peripheral surface of the main body, satisfies H greater than xc2xdxc3x97T.
Furthermore, the invention is provided by the coreless rubber crawler wherein the main cord is embedded in the main body such that the embedded depth H of the main cord, which is measured from an inner peripheral surface of the main body, satisfies H=xc2xdxc3x97T.
Moreover, the invention is provided by the coreless rubber crawler wherein the location of xc2xdxc3x97T is present between the main cord and the cord of the outermost layer.